Cinacalcet rectifies hypercalcemia in a patient with familial hypocalciuric hypercalcemia type 2 (FHH2) caused by a germline loss-of-function Gα11 mutation

C.M. Gorvin, F.M. Hannan, T. Cranston, Helena Valta, Outi Mäkitie, Camilla Schalin-Jäntti, R.V. Thakker

Research output: Contribution to journalArticleScientificpeer-review

Abstract

G-protein subunit -11 (G(11)) couples the calcium-sensing receptor (CaSR) to phospholipase C (PLC)-mediated intracellular calcium (Ca-i(2+)) and mitogen-activated protein kinase (MAPK) signaling, which in the parathyroid glands and kidneys regulates parathyroid hormone release and urinary calcium excretion, respectively. Heterozygous germline loss-of-function G(11) mutations cause familial hypocalciuric hypercalcemia type 2 (FHH2), for which effective therapies are currently not available. Here, we report a novel heterozygous G(11) germline mutation, Phe220Ser, which was associated with hypercalcemia in a family with FHH2. Homology modeling showed the wild-type (WT) Phe220 nonpolar residue to form part of a cluster of hydrophobic residues within a highly conserved cleft region of G(11), which binds to and activates PLC; and predicted that substitution of Phe220 with the mutant Ser220 polar hydrophilic residue would disrupt PLC-mediated signaling. In vitro studies involving transient transfection of WT and mutant G(11) proteins into HEK293 cells, which express the CaSR, showed the mutant Ser220 G(11) protein to impair CaSR-mediated Ca-i(2+) and extracellular signal-regulated kinase 1/2 (ERK) MAPK signaling, consistent with diminished activation of PLC. Furthermore, engineered mutagenesis studies demonstrated that loss of hydrophobicity within the G(11) cleft region also impaired signaling by PLC. The loss-of-function associated with the Ser220 G(11) mutant was rectified by treatment of cells with cinacalcet, which is a CaSR-positive allosteric modulator. Furthermore, in vivo administration of cinacalcet to the proband harboring the Phe220Ser G(11) mutation, normalized serum ionized calcium concentrations. Thus, our studies, which report a novel G(11) germline mutation (Phe220Ser) in a family with FHH2, reveal the importance of the G(11) hydrophobic cleft region for CaSR-mediated activation of PLC, and show that allosteric CaSR modulation can rectify the loss-of-function Phe220Ser mutation and ameliorate the hypercalcemia associated with FHH2. (c) 2017 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

Original languageEnglish
JournalJournal of Bone and Mineral Research
Volume33
Issue number1
Pages (from-to)32-41
Number of pages10
ISSN0884-0431
DOIs
Publication statusPublished - Jan 2018
MoE publication typeA1 Journal article-refereed

Fields of Science

  • ACTIVATION
  • BOVINE PARATHYROID CELLS
  • CALCIUM-SENSING RECEPTOR
  • CELL
  • COMPLEX
  • DISORDERS
  • DISORDERS OF CALCIUM
  • ENDOCRINE PATHWAYS
  • HEK293 CELLS
  • INSIGHTS
  • KINASE
  • PARATHYROID-RELATED DISORDERS
  • PHOSPHATE METABOLISM
  • PHOSPHOLIPASE-C
  • PROTEIN-COUPLED RECEPTORS
  • THERAPEUTICS
  • TISSUE SIGNALING
  • 3121 Internal medicine

Cite this

@article{3c8448452a834fd0864a222c1bdedab6,
title = "Cinacalcet rectifies hypercalcemia in a patient with familial hypocalciuric hypercalcemia type 2 (FHH2) caused by a germline loss-of-function Gα11 mutation",
abstract = "G-protein subunit -11 (G(11)) couples the calcium-sensing receptor (CaSR) to phospholipase C (PLC)-mediated intracellular calcium (Ca-i(2+)) and mitogen-activated protein kinase (MAPK) signaling, which in the parathyroid glands and kidneys regulates parathyroid hormone release and urinary calcium excretion, respectively. Heterozygous germline loss-of-function G(11) mutations cause familial hypocalciuric hypercalcemia type 2 (FHH2), for which effective therapies are currently not available. Here, we report a novel heterozygous G(11) germline mutation, Phe220Ser, which was associated with hypercalcemia in a family with FHH2. Homology modeling showed the wild-type (WT) Phe220 nonpolar residue to form part of a cluster of hydrophobic residues within a highly conserved cleft region of G(11), which binds to and activates PLC; and predicted that substitution of Phe220 with the mutant Ser220 polar hydrophilic residue would disrupt PLC-mediated signaling. In vitro studies involving transient transfection of WT and mutant G(11) proteins into HEK293 cells, which express the CaSR, showed the mutant Ser220 G(11) protein to impair CaSR-mediated Ca-i(2+) and extracellular signal-regulated kinase 1/2 (ERK) MAPK signaling, consistent with diminished activation of PLC. Furthermore, engineered mutagenesis studies demonstrated that loss of hydrophobicity within the G(11) cleft region also impaired signaling by PLC. The loss-of-function associated with the Ser220 G(11) mutant was rectified by treatment of cells with cinacalcet, which is a CaSR-positive allosteric modulator. Furthermore, in vivo administration of cinacalcet to the proband harboring the Phe220Ser G(11) mutation, normalized serum ionized calcium concentrations. Thus, our studies, which report a novel G(11) germline mutation (Phe220Ser) in a family with FHH2, reveal the importance of the G(11) hydrophobic cleft region for CaSR-mediated activation of PLC, and show that allosteric CaSR modulation can rectify the loss-of-function Phe220Ser mutation and ameliorate the hypercalcemia associated with FHH2. (c) 2017 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.",
keywords = "ACTIVATION, BOVINE PARATHYROID CELLS, CALCIUM-SENSING RECEPTOR, CELL, COMPLEX, DISORDERS, DISORDERS OF CALCIUM, ENDOCRINE PATHWAYS, HEK293 CELLS, INSIGHTS, KINASE, PARATHYROID-RELATED DISORDERS, PHOSPHATE METABOLISM, PHOSPHOLIPASE-C, PROTEIN-COUPLED RECEPTORS, THERAPEUTICS, TISSUE SIGNALING, 3121 Internal medicine",
author = "C.M. Gorvin and F.M. Hannan and T. Cranston and Helena Valta and Outi M{\"a}kitie and Camilla Schalin-J{\"a}ntti and R.V. Thakker",
year = "2018",
month = "1",
doi = "10.1002/jbmr.3241",
language = "English",
volume = "33",
pages = "32--41",
journal = "Journal of Bone and Mineral Research",
issn = "0884-0431",
publisher = "Wiley",
number = "1",

}

Cinacalcet rectifies hypercalcemia in a patient with familial hypocalciuric hypercalcemia type 2 (FHH2) caused by a germline loss-of-function Gα11 mutation. / Gorvin, C.M.; Hannan, F.M.; Cranston, T.; Valta, Helena; Mäkitie, Outi; Schalin-Jäntti, Camilla; Thakker, R.V.

In: Journal of Bone and Mineral Research, Vol. 33, No. 1, 01.2018, p. 32-41.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Cinacalcet rectifies hypercalcemia in a patient with familial hypocalciuric hypercalcemia type 2 (FHH2) caused by a germline loss-of-function Gα11 mutation

AU - Gorvin, C.M.

AU - Hannan, F.M.

AU - Cranston, T.

AU - Valta, Helena

AU - Mäkitie, Outi

AU - Schalin-Jäntti, Camilla

AU - Thakker, R.V.

PY - 2018/1

Y1 - 2018/1

N2 - G-protein subunit -11 (G(11)) couples the calcium-sensing receptor (CaSR) to phospholipase C (PLC)-mediated intracellular calcium (Ca-i(2+)) and mitogen-activated protein kinase (MAPK) signaling, which in the parathyroid glands and kidneys regulates parathyroid hormone release and urinary calcium excretion, respectively. Heterozygous germline loss-of-function G(11) mutations cause familial hypocalciuric hypercalcemia type 2 (FHH2), for which effective therapies are currently not available. Here, we report a novel heterozygous G(11) germline mutation, Phe220Ser, which was associated with hypercalcemia in a family with FHH2. Homology modeling showed the wild-type (WT) Phe220 nonpolar residue to form part of a cluster of hydrophobic residues within a highly conserved cleft region of G(11), which binds to and activates PLC; and predicted that substitution of Phe220 with the mutant Ser220 polar hydrophilic residue would disrupt PLC-mediated signaling. In vitro studies involving transient transfection of WT and mutant G(11) proteins into HEK293 cells, which express the CaSR, showed the mutant Ser220 G(11) protein to impair CaSR-mediated Ca-i(2+) and extracellular signal-regulated kinase 1/2 (ERK) MAPK signaling, consistent with diminished activation of PLC. Furthermore, engineered mutagenesis studies demonstrated that loss of hydrophobicity within the G(11) cleft region also impaired signaling by PLC. The loss-of-function associated with the Ser220 G(11) mutant was rectified by treatment of cells with cinacalcet, which is a CaSR-positive allosteric modulator. Furthermore, in vivo administration of cinacalcet to the proband harboring the Phe220Ser G(11) mutation, normalized serum ionized calcium concentrations. Thus, our studies, which report a novel G(11) germline mutation (Phe220Ser) in a family with FHH2, reveal the importance of the G(11) hydrophobic cleft region for CaSR-mediated activation of PLC, and show that allosteric CaSR modulation can rectify the loss-of-function Phe220Ser mutation and ameliorate the hypercalcemia associated with FHH2. (c) 2017 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

AB - G-protein subunit -11 (G(11)) couples the calcium-sensing receptor (CaSR) to phospholipase C (PLC)-mediated intracellular calcium (Ca-i(2+)) and mitogen-activated protein kinase (MAPK) signaling, which in the parathyroid glands and kidneys regulates parathyroid hormone release and urinary calcium excretion, respectively. Heterozygous germline loss-of-function G(11) mutations cause familial hypocalciuric hypercalcemia type 2 (FHH2), for which effective therapies are currently not available. Here, we report a novel heterozygous G(11) germline mutation, Phe220Ser, which was associated with hypercalcemia in a family with FHH2. Homology modeling showed the wild-type (WT) Phe220 nonpolar residue to form part of a cluster of hydrophobic residues within a highly conserved cleft region of G(11), which binds to and activates PLC; and predicted that substitution of Phe220 with the mutant Ser220 polar hydrophilic residue would disrupt PLC-mediated signaling. In vitro studies involving transient transfection of WT and mutant G(11) proteins into HEK293 cells, which express the CaSR, showed the mutant Ser220 G(11) protein to impair CaSR-mediated Ca-i(2+) and extracellular signal-regulated kinase 1/2 (ERK) MAPK signaling, consistent with diminished activation of PLC. Furthermore, engineered mutagenesis studies demonstrated that loss of hydrophobicity within the G(11) cleft region also impaired signaling by PLC. The loss-of-function associated with the Ser220 G(11) mutant was rectified by treatment of cells with cinacalcet, which is a CaSR-positive allosteric modulator. Furthermore, in vivo administration of cinacalcet to the proband harboring the Phe220Ser G(11) mutation, normalized serum ionized calcium concentrations. Thus, our studies, which report a novel G(11) germline mutation (Phe220Ser) in a family with FHH2, reveal the importance of the G(11) hydrophobic cleft region for CaSR-mediated activation of PLC, and show that allosteric CaSR modulation can rectify the loss-of-function Phe220Ser mutation and ameliorate the hypercalcemia associated with FHH2. (c) 2017 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

KW - ACTIVATION

KW - BOVINE PARATHYROID CELLS

KW - CALCIUM-SENSING RECEPTOR

KW - CELL

KW - COMPLEX

KW - DISORDERS

KW - DISORDERS OF CALCIUM

KW - ENDOCRINE PATHWAYS

KW - HEK293 CELLS

KW - INSIGHTS

KW - KINASE

KW - PARATHYROID-RELATED DISORDERS

KW - PHOSPHATE METABOLISM

KW - PHOSPHOLIPASE-C

KW - PROTEIN-COUPLED RECEPTORS

KW - THERAPEUTICS

KW - TISSUE SIGNALING

KW - 3121 Internal medicine

U2 - 10.1002/jbmr.3241

DO - 10.1002/jbmr.3241

M3 - Article

VL - 33

SP - 32

EP - 41

JO - Journal of Bone and Mineral Research

JF - Journal of Bone and Mineral Research

SN - 0884-0431

IS - 1

ER -